New research published in the International Journal of Food Science and Technology found steviol glycosides were not altered during the extraction and purification process to make high-purity stevia extract. The study was conducted at the University of Bonn in Germany, and provided further evidence for the naturality of stevia, a zero-calorie, plant-based sweetener.

To date, over 40 different steviol glycosides have been identified in the stevia plant. All of these have US generally recognised as safe (GRAS) status and have been approved by Health Canada, Food Standards Australia New Zealand (FSANZ) and, most recently, by the Joint Expert Committee on Food Additives (JECFA).

While the European Food Safety Authority (EFSA) is evaluating the approval of all 40-plus, they currently specify the use of eleven steviol glycosides in high-purity stevia leaf extracts.

This is the first study to systematically determine whether steviol glycosides are modified by typical commercial extraction and purification processes to obtain high-purity steviol glycoside sweeteners.

The study investigated whether commercial-scale extracted and purified steviol glycosides contained the same steviol glycoside pattern found in untreated leaves and the first water extract of stevia leaves, focusing on the nine steviol glycosides in the original JECFA specification (JECFA, 2010).

Three independent commercial-scale batches of stevia leaf, provided by PureCircle, Ltd, were studied. Each contained original dried stevia leaf, the first water extract, and a final 95 per cent purity stevia leaf extract end-product.

“Our results show commercial powders of extracted steviol glycosides provided by PureCircle, contain the same nine steviol glycosides analysed as the dried stevia leaves and their water extracts,” said Ursula Wölwer-Rieck, food chemist, Department of Nutritional and Food Sciences, University of Bonn, and the lead researcher.

“Results showed a similar distribution pattern from the three different stages of the process, demonstrating the nine steviol glycosides examined are not modified by extraction or purification processes,” she added.

“The fact there was no change of the nine steviol glycosides in the provided samples from the original plant to extracted sweetener supports the natural authenticity of stevia sweeteners,” Wölwer-Rieck said.

Stevia is extracted and purified from the plant into a powdered sweetener. This involves steeping the dried leaves, and separating and purifying steviol glycosides.

“Given the growing global concerns about obesity and diabetes and the United States labelling regulations which will require added sugars to be listed on food labels, stevia will help food and beverage companies reduce sugar and calories in products,” said Priscilla Samuel, director, Global Stevia Institute.

“Consumers’ desire for plant-based, zero-calorie sweeteners and clean labels have contributed to stevia’s growth,” she added.